In the field of testing and measuring the print quality of certain inks deposited on selected print media, it is known that the media print quality is related to the fluid (ink) penetration rate therein. The wetting delay of the fluid, or the time between initial fluid contact and initial fluid penetration, and the fluid penetration rate into the print media have been shown to closely correlate with ink jet print quality. That is, rapid fluid penetration rates and short wetting delays are indicative or a poor ink jet print quality or porous media injected with aqueous based inks.
One prior approach to measuring the print quality of aqueous based as well as other kinds of inks was developed by J. A. Bristow in 1967 and is described in an article by J. A. Bristow entitled "Liquid Absorption Into Paper During Short Time Intervals", Svensk Papperstidning, 19, Oct. 15, 1967. In the above Bristow process, a special type of ink jet head box is initially filled with a metered amount of the fluid under study. This head box is then placed in contact with the porous ink-receiving surface under study, and this surface is attached to a rotating wheel. By measuring the length of an ink trace for a number of different wheel speeds, a plot of the amount of fluid transferred into the porous material versus the time that the ink jet head box is in contact with the porous material can be developed for each of the wheel speeds. From this information, three parameters relating to the fluid penetration dynamics may be obtained, namely: (1) the volumetric roughness of the print medium, (2) the wetting delay of fluid penetration into the print medium and (3) the fluid penetration rate into the print medium.
Whereas the above described Bristow test has proven satisfactory in some respects, this process may take up to two to three hours to complete, and the test results obtained using the above Bristow method have been less than reliable in all circumstances. In addition, the equipment required by the Bristow method is sometimes awkward to set up and operate when collecting data during a plurality of head box runs in order to develop a plot having the multiple parameters described above.